Supermodel Christy Turlington – a longtime smoker who became a passionate anti-smoking crusader after losing her father to lung cancer – has disclosed she has early-stage emphysema.

The former catwalker, 31, who gave up cigarettes when she was 26, learned she had the lung condition after volunteering for a scan at New York Weill Cornell Medical Center, it was reported yesterday.

The yoga-loving model, whose work for Calvin Klein made her face internationally famous, will appear in an anti-smoking TV ad campaign in Britain to air at Christmas.

“I am 31, and I smoked years ago. And I have early-stage emphysema,” the Times of London quoted her as saying.

“I’ve only just got the results of the test, and I have to go back in a year for more tests.”

The supermodel said she does not find the condition debilitating, the newspaper said.

Turlington spokeswoman Amy Swift told The Post yesterday that “Christy is perfectly healthy and has been a nonsmoker for six years. Early stages of emphysema are frequently found in people who have smoked, and early reports of this story were grossly exaggerated.”

Dr. Claudia Henschke, a Cornell University radiology professor who analyzed her scan, said she does not expect the disease to get worse because Turlington no longer smokes, The Times of London said.

The newspaper also quoted Henschke as saying treatments are being developed that might reverse early-stage emphysema.

Rami Bachiman, a spokesman for the American Lung Association, said emphysema is a “chronic lung disease mainly caused by smoking in which the air sacs lose their elasticity so people have a problem breathing.”

“In the early stage they may notice they have trouble doing things they used to do without feeling they’re running out of breath,” he told The Post.

“It can be an exhausting kind of disease. Depending on how far the disease has progressed, some people may constantly struggle to take their next breath. At some point many would need supplemental oxygen even to do ordinary chores around the house.”

A yoga devotee who last year got her undergraduate degree from New York University and has become a businesswoman and author, Turlington began smoking when she was 13.

Her dad, Dwain Turlington, a Pan Am pilot, died of lung cancer in 1997.

“I idolized and admired him and mourned him for a long time,” The Times quoted her as saying.

“Now I want to use the experience to reach out to others struggling with tobacco.”